The characteristics of photoluminescence at GaAs/AlGaAs interface

Yuan, Y. R.; Merz, J. L.; Vawter, G.A.

doi:10.1016/0022-2313(88)90423-1

Cited by 3 publications

(2 citation statements)

References 4 publications

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“…The earliest proposal suggested that the e and d lines result from recombination of free and donor-bound electrons with 2D interfacial holes (23,25). Soon after, an excitonic model was proposed (26). More recent results support this and attribute the energy shift between H-band and bulk excitons to a spatially indirect character of H-band states caused by their localization in the tail of the interfacial E field (27,28).…”

Section: The Optical and Power Nmr Combinationsupporting

confidence: 52%

“…The resulting advantages are selectivity to optically relevant sites and Ϸ10 5 -fold sensitivity gain (in addition to that from ONP) relative to traditional inductive detection of NMR. The nature of the electronic states that give rise to the H-band PL has been a matter of some debate (25)(26)(27)(28). The earliest proposal suggested that the e and d lines result from recombination of free and donor-bound electrons with 2D interfacial holes (23,25).…”

Section: The Optical and Power Nmr Combinationmentioning

confidence: 99%

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Imaging quantum confinement with optical and POWER (perturbations observed with enhanced resolution) NMR

Kempf

Miller

Weitekamp

2008

Proc. Natl. Acad. Sci. U.S.A.

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The nanoscale distributions of electron density and electric fields in GaAs semiconductor devices are displayed with NMR experiments. The spectra are sensitive to the changes to the nuclear-spin Hamiltonian that are induced by perturbations delivered in synchrony with a line-narrowing pulse sequence. This POWER (perturbations observed with enhanced resolution) method enhanced resolution up to 10 3 -fold, revealing the distribution of perturbations over nuclear sites. Combining this method with optical NMR, we imaged quantum-confined electron density in an individual AlGaAs/GaAs heterojunction via hyperfine shifts. Fits to the coherent evolution and relaxation of nuclei within a hydrogenic state established one-to-one correspondence of radial position to frequency. Further experiments displayed the distribution of photoinduced electric field within the same states via a quadrupolar Stark effect. These unprecedented high-resolution distributions discriminate between competing models for the luminescence and support an excitonic state, perturbed by the interface, as the dominant source of the magnetically modulated luminescence.GaAs ͉ hyperfine or Knight shift ͉ Stark effect ͉ H-band photoluminescence I maging electron distributions and the electrostatic potentials that govern their transfer is a longstanding goal in diverse fields. Spin or charge transfer defines function in systems for photovoltaic and photosynthetic energy capture, ion channels, enzyme catalysis, spintronics, and molecular and nanoscale electronics. Success in imaging nanoscale electronic properties can lead to mechanistic understanding and provide guidelines to tune device performance or to modify natural systems for specialized applications. With its atomic-scale capabilities for nondestructive, noninvasive spectroscopy and imaging, NMR seems well suited to such characterization. However, NMR of solids is hampered by broad spectral lines because of static interactions that prevent measurement of small differences between sites that might otherwise reveal local electronic features with atomic detail.Here, we present a general method whereby solid-state NMR surmounts this challenge and then apply it to image distributions of spin density and electric (E) field within an electronic state with dimensions (Ϸ10 nm) distributed over Ϸ10 5 nuclei. The POWER (perturbations observed with enhanced resolution) NMR approach, encodes small responses to a sample perturbation that is switched in synchrony with an NMR multiple-pulse line-narrowing sequence. The sequence removes the otherwise obscuring clutter of static spin interactions to yield a spectrum dominated by the desired perturbation with up to 3 orders-ofmagnitude resolution enhancement. To further obtain the sensitivity and selectivity needed to isolate signals of local, nanoscale features from the bulk signal of a macroscopic sample, we combined the POWER approach with methods for optical NMR (ONMR). By using both optical nuclear polarization (ONP) (1-15) and optical detection (2-4, 6, 7, 9-13), O...

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Section: The Optical and Power Nmr Combinationsupporting

confidence: 52%

Section: The Optical and Power Nmr Combinationmentioning

confidence: 99%

Imaging quantum confinement with optical and POWER (perturbations observed with enhanced resolution) NMR

Kempf

Miller

Weitekamp

2008

Proc. Natl. Acad. Sci. U.S.A.

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show abstract

Quantum-confined excitonic states at high-quality interfaces in GaAs(ntype)/AlxGa1
Gd
¹
,
Dj
²
,
Tf
³

et al. 1991
Phys. Rev. B
13
1
4
0
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Luminescence kinetics of intrinsic excitonic states quantum-mechanically bound near high-quality (n−-type GaAs)/(p-typeAl
Gilliland
¹
,
Wolford
²
,
Kuech
³

et al. 1994
Phys. Rev. B
21
0
2
0
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The characteristics of photoluminescence at GaAs/AlGaAs interface

Cited by 3 publications

References 4 publications

Imaging quantum confinement with optical and POWER (perturbations observed with enhanced resolution) NMR

Imaging quantum confinement with optical and POWER (perturbations observed with enhanced resolution) NMR

Quantum-confined excitonic states at high-quality interfaces in GaAs(ntype)/AlxGa1
Gd
¹
,
Dj
²
,
Tf
³

et al. 1991
Phys. Rev. B
13
1
4
0
View full text Add to dashboard Cite

Luminescence kinetics of intrinsic excitonic states quantum-mechanically bound near high-quality (n−-type GaAs)/(p-typeAl
Gilliland
¹
,
Wolford
²
,
Kuech
³

et al. 1994
Phys. Rev. B
21
0
2
0
View full text Add to dashboard Cite

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The characteristics of photoluminescence at GaAs/AlGaAs interface

Cited by 3 publications

References 4 publications

Imaging quantum confinement with optical and POWER (perturbations observed with enhanced resolution) NMR

Imaging quantum confinement with optical and POWER (perturbations observed with enhanced resolution) NMR

Quantum-confined excitonic states at high-quality interfaces in GaAs(ntype)/AlxGa1Gd1, Dj2, Tf3 et al. 1991Phys. Rev. B13140View full textAdd to dashboardCite

Luminescence kinetics of intrinsic excitonic states quantum-mechanically bound near high-quality (n−-type GaAs)/(p-typeAlGilliland1, Wolford2, Kuech3 et al. 1994Phys. Rev. B21020View full textAdd to dashboardCite

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Quantum-confined excitonic states at high-quality interfaces in GaAs(ntype)/AlxGa1
Gd
¹
,
Dj
²
,
Tf
³

et al. 1991
Phys. Rev. B
13
1
4
0
View full text Add to dashboard Cite

Luminescence kinetics of intrinsic excitonic states quantum-mechanically bound near high-quality (n−-type GaAs)/(p-typeAl
Gilliland
¹
,
Wolford
²
,
Kuech
³

et al. 1994
Phys. Rev. B
21
0
2
0
View full text Add to dashboard Cite